1. Field of the Invention
This invention relates to a stamp-making apparatus for making a stamp big printing an image forming a stamp impression of the stamp on an ink ribbon, and exposing a stamp-making object material mounted in the stamp-making apparatus to ultraviolet rays irradiated through the mask of the ink ribbon, as well as to a function changeover mechanism for switching between functions of printing, exposure, etc., of the stamp-making apparatus, an exposure system forming a source of exposure light to which a stamp-making object material is exposed, and a stamp object material-detecting device therefor.
2. Prior Art
Conventionally, a stamp-making apparatus of the above-mentioned kind includes a supply reel for rolling out an ink ribbon therefrom and a take-up reel for taking up the ink ribbon therein, as well as a presser plate for pressing the ink ribbon against a stamp body as a stamp-making object material from which a stamp is made, with she presser plate and the stamp body being arranged on opposite sides of a feed path of the ink ribbon in a manner facing toward each other. On upstream and downstream sides of the stamp body and the presser plate, a pair of rollers are provided for guiding the ink ribbon to a feed path between the stamp body and the presser plate such that the ink ribbon is fed in parallel with the stamp body and the presser plate. When exposure of the stamp body to light is conducted, the ink ribbon is stopped in a position in which a portion of the ink ribbon on which an image of a stamp impression (stamp image) is formed faces toward the stamp body, and then a translating mechanism, not shown, operates to move the presser plate forward to the stamp body and then the exposure of the stamp body is carried out (Japanese Laid-Open Patent Publication (Kokai) No. 6-278350).
As a light source for exposure, a self-heating hot-cathode tube, i.e. a so-called semi-hot tube is used. To detect expiration of the service life or failure of the self-heating hot-cathode tube, a pair of overtemperature cutouts are provided on electrode portions at opposite ends of the self-heating hot-cathode tube such that they each extend along a longitudinal axis of the same. That is, the overtemperature cutouts each having a column shape are provided such that they are brought into contact with the self-heating hot-cathode tube in parallel therewith.
Further, in a stamp-making object material-detecting apparatus of the above-mentioned kind, a stamp body (stamp-making object material) is mounted in a pocket of a stamp-making apparatus from above such that it lies on its side with a stamp surface to be formed facing in a forward direction, and a state of the stamp body being mounted in the pocket is detected by a sensor or a switch provided at the bottom of the pocket of the stamp-making apparatus.
In a conventional stamp-making apparatus, when the feed path of an ink ribbon is long, it is required to feed the ink ribbon while applying a predetermined level of tension thereto so as to prevent the ink ribbon from becoming loose. In particular, if the ink ribbon is fed with the width of a ribbon surface extending perpendicularly, i.e. on its side on a horizontal plane, the ink ribbon can fall off a feed roller or the like when it becomes loose, and therefore it is necessary to feed the ink ribbon in a strongly stretched state to avoid jamming. However, the ink ribbon is thin, and made of material having no rigidity, so that if the ribbon is sent in a strongly stretched state, vertical wrinkles are formed crosswise to the direction of feed of the ink ribbon.
On the other hand, if exposure of the stamp-making object material to light is carried out using the ink ribbon as a mask, reproducibility of the exposure is degraded due to diffusion of light unless the ink ribbon is brought into intimate contact with the stamp-making object material. Therefore, it is considered best to urge the ink ribbon against the stamp-making object material by means of a transparent presser plate. However, if a tensioned ink ribbon is simply urged against the stamp-making object material, exposure is effected with vertical wrinkles formed on the ink ribbon and the stamp image being deformed due to elongation of the ink ribbon. Inversely, if the ink ribbon is made loose during exposure, position of the stamp image on the ink ribbon with respect to the stamp-making object material is displaced.
Further, in a conventional stamp-making apparatus, if a print head for printing, the presser plate for exposure or the like is moved in an electrical manner by the use of electrical means such an electric motor, the apparatus becomes complicated not only in construction but also in the method of control, which increases the manufacturing costs of the stamp-making apparatus. Therefore, it is preferred that the print head and the presser plate should be directly moved in a mechanical manner, from the viewpoint of cost and reliability of the movement of these members. However, if operating members are provided for moving these members, respectively, the manner of operating these operating members becomes complicated and wrong operations are liable to occur.
Further, in this kind of the stamp-making apparatus, exposure to ultraviolet rays is carried out, and hence it is necessary to hold the stamp-making object material in an unmovable manner in carrying out the exposure and prevent invasion of dust to an exposure block. To this end, it is preferred that the apparatus is provided with a mounting block for receiving the stamp-making object material therein with a lid for opening and closing the mounting block. However, if the lid has a simple opening and closing structure, the lid can be opened by mistake during exposure, to undesirably allow ultraviolet rays to leak to the outside. Further, if the lid is opened during printing, the ink ribbon is jammed.
The semi-hot tube forming part of the exposure system is small-sized and has a preheating circuit simple in circuit configuration compared with a hot-cathode tube which is large in diameter and has a preheating circuit complicated in circuit configuration. The semi-hot tube generates sufficient quantity of light compared with a cold-cathode tube which generates insufficient quantity of light. Therefore, the semi-hot tube is very useful for a luminescent tube installed in electronic devices and required to generate a substantial quantity of light. If an abnormality-detecting device is provided on such a semi-hot tube, in a conventional manner, such that overtemperature cutouts extend along the tube in a line contact manner, more heat readily dissipates from the semi-hot tube to the overtemperature cutouts when the semi-hot tube starts to be energized, resulting in a delayed production of sufficient quantity of light.
On the other hand, in the case of a conventional stamp-making object material-detecting device, if stamp bodies (stamp-making object materials) which are different in shape are mounted, some of them can be spaced from the bottom of the pocket, which causes a sensor or a switch for detecting the stamp bodies to operate in an inaccurate manner. On the other hand, if the stamp bodies are mounted in the pocket such that L-hey are pressed against the bottom of the pocket, the position of the stamp-forming surface is varied among the stamp bodies.